Choosing one item from stimulus list?

Here is a description of the experiment I’m working on:

Each trial begins with a center stimulus on the screen. After pressing the space bar, a peripheral stimulus appears on the screen in a varied location. Trial types include a gap condition, where the center stimulus disappears; and an overlap condition, where the center stimulus remains on the screen.

The problem I am having, is that while I can create separate trials and events for each different center stimulus, I cannot do that for the peripheral stimulus while still making it random. When I try to use stimulus lists, it won’t just choose one stimulus, and move on to the next trial–it insists on using every stimulus on the list in sequential order.

I have attached the experiment, if it helps.


Attention.sl4 (11.1 KB)

Please post as an Experiment Package, which is found under the File menu within SuperLab. I can’t run your experiment without the files.

Sorry for the delay, I was getting an error while trying to create the package. I attached the .zip file. (5.66 MB)

Have you tried randomizing the trials within the block? This is done on the block level.

As I understand it, that would still require making separate trials for every event combination. That’s a whole lot of trials. I’m hoping there’s an easier way, is there?

When you randomize the trials in the block, your stimulus lists will be shown in a random order. To get a better idea of how SuperLab is interpreting this, go to the Experiment menu and select Expand Events that Use Lists.